In order to improve the filtering performance of a torsional damper, one can opt to use longer and wider springs and to arrange them along longer installation radii in windows of the damper. In the case in which that damper is integrated into a friction disk for a clutch, the springs generate a force acting against rotation of the guide washers of the disk with respect to a web of the disk. With a dimension and positioning of this kind, at high rotation speeds of the vehicle's engine the springs produce large centrifugal forces, capable of damaging the web and/or the guide washers along with the radially external edges of the windows with which they come into contact. This contact can in fact generate significant wear on, and even breakage of, these parts as well as hysteresis peaks that affect the filtering performance of the damper.
In order to solve this problem it is known, for example from the Application FR 2 732 426, to equip each angular end of a spring with a seat that comes into abutment against the web in order to absorb the centrifugal forces. Such seats do not make it possible, however, to prevent the springs from coming into contact with the radially external edges of the windows of the web or of the guide washers above a certain engine rotation speed.
There is a need to reduce wear on those element(s) of the damper with which the springs can come into contact in response to centrifugal forces associated with rotation of the vehicle's engine, including at high rotation speeds.